New FinCEN Proposed Requirements for Certain Cryptocurrency Transactions [pdf]
public-inspection.federalregister.gov3 pointsby shanecoin0 comments
James Ashley authored and JesseKPhillips committed on Dec 6, 1986
8th Congress authored and JesseKPhillips committed on Jun 15, 1980
The Ethereum protocol was designed with PoS in mind and has a built-in difficulty bomb[1] to prove it. In short, this difficulty bomb makes it exponentially harder to mine ETH over time. The goal of this feature was to encourage all participants of the ecosystem to transition to PoS as quickly as possible.
Given that, the implementation has not worked out totally as expected, as the difficulty bomb has been pushed back a few times over the years. However, to answer your question, the reason they did not move faster is because this transition is hard and plays in some uncharted territory.
[1] https://medium.com/fullstacked/the-ice-age-is-coming-ee5ad5f...